Adhesion to the body is a complicated process that is necessary to the functionality of a wide variety of products including but not limited to wound care dressings and ostomy appliances. It is known that adhesion to the skin for prolonged periods of time requires management of perspiration and other trans-epidermal water losses (TEWL). Pressure sensitive adhesives containing water-absorbing powders have been found effective in TEWL management. In particular, hydrocolloid adhesives are especially effective, and are preferred for this purpose.
It is common practice to manage wounds by covering them with a hydrocolloid wound dressing. These dressings typically consist of a pressure sensitive adhesive into which has been dispersed hydrocolloid particles. U.S. Pat. Nos. 3,339,546, 4,551,490, and others comprising the prior art of hydrocolloid containing pressure sensitive adhesives demonstrate this practice. Hydrocolloid wound dressings are exceptional in their ability to manage wound exudate. They achieve long wearing times, and provide a moist wound healing environment. This environment promotes autolytic debridement of the wound, non-traumatic dressing removal, and many other improvements over conventional adhesives and dressings that are believed to be beneficial to wound healing.
While hydrocolloid adhesives are known for the valuable characteristics described above, one limitation is their short-term rate of absorption. Typically the moisture absorbing capacity of a hydrocolloid adhesive is exceptional, and can exceed 5000 grams per square meter per day (gsm/d). However, absorption during the first hour is typically below 1000 gsm/d, and proportionally less at shorter times. As a result, hydrocolloid wound dressings are effective for a certain range of wounds, which produce light to moderate exudate. For heavily exudating wounds, the inability of hydrocolloid dressings to manage exudate leads to leakage of wound fluid sometime during the first 24 hours of wear.
For heavily exudating wounds, foamed polymers coated with a pressure sensitive adhesive on their wound contact surface are sometimes used. It is believed that their familiar design similar to strip bandages or gauze) and ability to absorb wound exudate relatively quickly are factors in their selection. However, these products suffer from several limitations. Unlike hydrocolloid wound dressings, these products are not noted for the preferred wound healing capabilities of hydrocolloid dressings. Further, they typically have limited long term absorbing capacity as their absorbency results primarily from a mechanical effect produced by the pores and cells of their foamed structure. Obviously, an additional limitation of conventional foamed dressings is that they will lose moisture when compressed. Finally, as the wound contact surface may be coated with a pressure sensitive adhesive to adhere to the body, the wound may be traumatized upon removal of the conventional foam dressing when that adhesive bonds to the healing wound itself.
As an ostomy device, a foamed hydrocolloid adhesive skin barrier offers several benefits over the state of the art. Flexibility of the skin barrier is greatly enhanced compared with a non-foamed barrier of the same composition. A secure attachment to the skin can be achieved, while reducing the removal force by virtue of the lessened contact area. As for wound dressings, intimate contact between hydrocolloid adhesives and the skin of an ostomate is well established as a beneficial attribute. Finally, the ability of the foamed structure to conform to irregular surfaces of the body to which an ostomy device must be attached is improvement over non-foamed adhesives.